South Africa has the world’s deepest gold mines and an earth tremor at one of Sibanye-Stillwater’s mines killed seven miners in one incident alone in May. In all 24 of its workers have been killed this year.

Sibanye, which also produces platinum, said adjusted earnings before interest, tax, depreciation and amortization (EBITDA) totalled 1.6 billion rand ($109 million) in the three months to September, down from 2.7 billion rand a year earlier.

Shares in Sibanye-Stillwater hit a monthly low on Thursday, down 13.28 percent at 8.88 rand by 0931 GMT.

“If you look at the operating update it doesn’t make for pretty reading and the market is taking the view that it doesn’t like it,” said Ryan Woods, market trader at Independent Securities.

As well as production cuts, the miner also had to defer some U.S. sales in September until October at the request of a client, a precious metals refiner, it said.

The miner said comparable gold output at its South Africa operations fell 24 percent to 284,600 ounces in the quarter after the rehabilitation of seismically affected production areas and the suspension of underground mining at its Cooke operations.

The firm revised its 2018 guidance for its local gold operations down to between 1.13 million ounces and 1.16 million ounces, from previous guidance of between 1.17 million ounces and 1.21 million ounces.

Platinum group metals (PGM) production from the group’s South African operations fell to 305,227 ounces in the third quarter from 306,184 ounces a year earlier, while output at its U.S operations rose 3 percent year-on-year to 139,178 ounces.